view tests/test-empty-file.t @ 19929:ab2362e1672e

merge: exit early during a no-op update (BC)

hg update . (or equivalents) are effectively no-ops in just about all
circumstances.  These sorts of updates can be especially common in a
bookmark-oriented workflow. This saves us a status check and a manifest
decompression, which means that on a repo with over 210,000 files, this brings
hg update . down from 2.5 seconds to 0.15.

There is one change in behavior: a file that was added, not committed, and then
deleted but not removed used to be removed from the dirstate. With this patch
it isn't. This is what causes the change in test-mq-qpush-exact.t. This seems
like it's enough of an edge case to not be worth handling.

The output of test-empty.t changes because those files are not yet created.

  $ hg init a
  $ cd a
  $ touch empty1
  $ hg add empty1
  $ hg commit -m 'add empty1'

  $ touch empty2
  $ hg add empty2
  $ hg commit -m 'add empty2'

  $ hg up -C 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ touch empty3
  $ hg add empty3
  $ hg commit -m 'add empty3'
  created new head

  $ hg heads
  changeset:   2:a1cb177e0d44
  tag:         tip
  parent:      0:1e1d9c4e5b64
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     add empty3
  
  changeset:   1:097d2b0e17f6
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     add empty2
  

  $ hg merge 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

Before changeset 05257fd28591, we didn't notice the
empty file that came from rev 1:

  $ hg status
  M empty2
  $ hg commit -m merge
  $ hg manifest --debug tip
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty1
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty2
  b80de5d138758541c5f05265ad144ab9fa86d1db 644   empty3

  $ cd ..